Cutter head for a dry shaver

ABSTRACT

A CUTTER HEAD FOR A DRY SHAVER WITH A PERFORATED CUTTER FOIL AS UPPER CUTTER AND LOWER CUTTERS WITH A TRIMMER AND DRIVING CONNECTIONS FOR THE CUTTER MEMBERS AND A SPRING ARRANGEMENT FORMED BY TWO SPRINGS LYING MECHANICALLY IN SERIES, OF WHICH ONE ABUTS WITH ONE END   ON THE CUTTER HEAD FRAME, AND THE OTHER ABUTS WITH ONE END ON THE LOWER CUTTER FOR THE RAZOR PART, WHILE THE OTHER ENDS OF THE TWO SPRINGS ARE IN OPERATING CONNECTION WITH THE LOWER CUTTER FOR THE TRIMMER.

Jan. 12, 1971 R. KONIG 3,553,337

7 CUTTER HEAD FOR A DRY SHAVER f Filed Jan. 8, 1969 2 Sheets-Sheet 1 INVENTOR Red'vvzarz K572 L9 Y M '22; ORNEYJ Jan. 12, 1971 R. KUNIG 3,553,837

' CUTTER HEAD FOR A DRY SHAVER Filed Jan. 8, 1969 2 Sheets-Sheet 2 INVENTOR Rein Z3 ICZ K577? Maw ATTORNEXg United States Patent 3,553,837 CUTTER HEAD FOR A DRY SHAVER Reinhard Kiinig, Krumpendorf, Carinthia, Austria, as-

signor to Firma Cariuthia Elektrogerate Gesellschaft m.b.H., Klagenfurt, Carinthia, Austria Filed Jan. 8, 1969, Ser. No. 789,859 Claims priority, application Austria, Jan. 12, 1968, A 365/68 Int. Cl. B26b 19/10 US. Cl. 30-341 7 Claims ABSTRACT OF THE DISCLOSURE In dry shavers there is a known construction of the cutter head, in which a perforated cutter foil acting as upper cutter for the razor part is arranged on a frame, and at least on one longitudinal side of the frame is arranged an upper cutter for at least one trimmer, and these stationary upper cutters co-operate with reciprocating driven lower cutters, resiliently pressed against them.

In a known construction of cutter head of this kind, the lower cutter for the razor part, which cooperates with the perforated cutter foil, is made integral with the lower cutter of the trimmer, so that both lower cutters can be driven in unison. Springs, acting against this unitary part which forms the lower cutters, provide for pressing against the associated upper cutters. With this construction of the lower cutters as a unitary component, uneven engagement of the lower cuters with the associated upper cutters can occur, so that either only the one or the other lower cutter engages fully with the associated upper cutter. Moreover, with this construction, the springs in operation perform a tilting motion, which leads to an uneven pressing of the lower cutters on the associated upper cutters, so that a full engagement of the cutters on one another is not ensured. A satisfactory engagement of the cutting surfaces of the co-operating cutters is, how- I ever, very important for a satisfactory shaving or trimming action.

In another known cutter head construction, of the kind mentioned in the introduction, the lower cutters for the razor part and for the trimmer are made separately from one another. These separate lower cutters are each pressed against the associated upper cutter by a spring arrangement. In this way, a better engagement of the cutting surfaces of the co-operating cutters is indeed ensured, but the separate arrangement of springs gives an expensive total construction and also a relatively complicated assembly of the indivdual parts.

Furthermore, for a cutter head with a perforated cutting foil, but with no trimmer, which cooperates with a lower cutter of several pieces, it has already been proposed to arrange the lower cutter parts on a common carrier, on which they are loosely secured by springs. At the same time the carrier itself is arranged with springs in the cutting head frame and is reciproated by the drive of the apparatus. This arrangement has the disadvantage that the lower cutter parts do not exactly follow the motion of the carrier, because by reason of their inertia they lag behind the movement of the carrier, so that the amplitude of oscillation is reduced. The springs between the carrier and the parts of the lower cutter likewise perform tipping movements, which influence the full engagement of the lower cutter parts on the perforated cutting foil.

These disadvantages are eliminated in a cutter head of the kind described in the introduction, in which the lower cutters for the razor part and the trimmer are made separate from one another, while retaining a simple total construction, in that, in accordance with the invention, for pressing the lower cutter of the razor part against the perforated cutter foil, there serves as least one spring arrangement, which contains two springs lying mechanically in series, of which one abuts with one end on the cutter head frame, and the other with one and on the lower cuter for the razor part, while the other ends of the two springs are in operating connection with the lower cutter for the trimmer, while the strength of the springs which abut the cutter head frame, and press the lower cutter for the trimmer against the associated upper cutter is greater than the strength of the springs abuting against the lower cutter for the razor part, and while, to produce uniform drive of the two lower cutters, there is provided a driving connection between these, and the drive of the dry shaving apparatus only engages directly on one of the two lower cutters.

By this means, in a simple manner, there is achieved that the spring arrangement presses both the lower cutter for the razor part, and also the lower cutter for the trimmer, against the associated upper cutter, without a rigid connection between the lower cutters being present. But the drive of the two lower cutters nevertheless occurs in unison. In this way the advantage is attained, that the springs, which abut against the lower cutter of the razor part, are not exposed to any tipping load, so that in the operation of the apparatus, they remain always perpendicular to the lower cutter of the razor part and are displaced parallel to themselves. By this means the force, with which the lower cutter for the razor part is pressed against the associated upper cutter, is constant at every stage of the movement, so that an especially uniform engagement of the lower cutter of the razor part with the perforated cutter foil is ensured, which, as mentioned, is decisive for a good shaving performance.

Advantageously, an intermediate member is provided as a driving connection, which on the one hand is connected to one of the two lower cutters pivotally, and moveable perpendicular to its reciprocating direction of motion, and on the other hand is connected fixedly to the other lower cutter, for example with snap connec tions.

A particularly simple construction can be obtained with a cutter head, in which the lower cutter for the razor part has a driving bar, with which a fork-shaped driving member of the dry shaver engages, in that the intermediate member is arranged on the driving bar of the lower cutter of the razor part by means of two lugs having longitudinal slits, and the lower cutter for the trimmer is fixedly connected to the intermediate member.

Moreover, it has been found to be advantageous, if two spring arrangements are provided, and the intermediate member is formed as a frame extending between the cutter head frame and the lower cutter for the razor part, while each of the two springs of a spring arrangement engages on a short side of the frame. Advantageously with this arrangement, the intermediate member is guided in its longitudinal direction by its longitudinal frame sides on sliding surfaces of the cutter head frame. By this means, the intermediate member acts as a unitary holding and guiding portion for the spring arrangements, so

that a further improvement with reference to the engagement of the lower cutters with the associated upper cutters is achieved.

In a cutter head, in which the intermediate member is fixedly connected with the lower cutter of the trimmer, the intermediate member advantageously has abutment surfaces, with which the lower cutter for the razor part comes into engagement during use of the razor part, by reason of the additional razor pressure which arises, so soon as this exceeds the strength of the spring of each spring arrangement which abuts the lower cutter of the razor part. Then with high shaving pressure, the lower cutter for the razor part engages with the intermediate member, and carries this with it, so that the lower cutter which is coupled to the intermediate member is also taken with it and thus lifted away from the upper cutter associated with it. This ensures that during the use of the razor part, the friction in the trimmer is as far as possible reduced, or totally removed, and thus more power is available for the drive of the razor part. This advantage can also be simply achieved in a cutter head according to the invention, in that the force of the spring of each spring device supported by the cutter head frame is exactly chosen to be so much greater than that of the spring which abuts against the lower cutter for the razor part, that during use of the razor part, by the additional shaving pressure, the lower cutter of the trimmer is lifted away from its upper cutter.

The invention will be further explained below with reference to the drawings, in which certain constructional examples are shown, but to which it is not however to be restricted.

FIG. 1 shows in longitudinal section and FIG. 2 in section on the line IIII in FIG. 1 a first constructional example, in which two spring arrangements containing coil springs are provided.

In FIG. 3 a second constructional example is shown, again in longitudinal section, and in FIG. 4 in section on the line IVIV in FIG. 3, in which the driving connection between the lower cutters takes place through an intermediate member.

FIG. 5 shows a further constructional example, in which the spring arrangements contain springs of a different kind.

In FIG. 6 an example with a single spring arrangement is shown, in longitudinal section, and in FIG. 7 in section on the line VIIVII in FIG. 6.

In the cutter head according to FIGS. 1 and 2, a cutter head frame is indicated at 1, on which is arranged a perforated cutter foil 2, as the upper cutter for the razor part. Along the longitudinal side 3 of the frame extends the upper cutter 4 of a trimmer, having cutter teeth. Lower cutters 5 and 6 respectively each co-operate with these two stationary upper cutters. The lower cutter 5 which co-operates with the perforated cutter foil, is for this purpose made curved in shape, and consists of individual strips, the cutting edges of which are shown schematically by lines 7; bars 8 serve to stiffen the lower cutter. The lower cutter 6 of the trimmer is formed by a plate, which carries a row of cutter teeth 9 on one longitudinal side.

To press the lower cutters against the associated upper cutters, two spring arrangements 10 are now provided, while each consists of two springs 11 and 12 lying mechanically in series. The springs 11 at the same time abut with one end against the cutter head frame 1, and the springs 12 at the same time each abut with one end against a bar 8 of the lower cutter 5 for the razor part. The other ends of the two springs 11, 12 are connected together through double spring discs 13, which in turn are in operative connection with the lower cutter 6 of the trimmer, in that they are fitted in openings 14 in the lower cutter plate. The strength of the springs 11 is greater than the strength of the springs 12, so that the springs 11, via the spring discs 13, press the lower cutter 6 of the trimmer with the row of cutting teeth 9 against the upper cutter 4 of the trimmer, while the edge of the lower cutter plate 6 lying opposite to the row of teeth 9 abuts a strip 15 provided on the cutter head frame, and the springs 12 press the lower cutter 5 for the razor part into the curved concave perforated cutter foil 2. In this way the upper and lower cutters both of the razor part and of the trimmer engages one another fully.

The two lower cutters 5 and 6 are in themselves separate components. However there is provided a driving connection between them, which ensures an identical working motion for both lower cutters, so that the drive of the dry shaving apparatus need only engage one of the lower cutters.

In the case being considered, the connection is formed by a pin 16 provided on the lower cutter 5 for the razor part, which extends, with some play, through openings 17 in the lower cutter plate 6 of the trimmer. Furthermore, on the lower cutter 5 for the razor part there is arranged a driving pin 18, with which engages a forkshaped oscillating lever 20- of the drive portion of the dry shaver arranged in the housing 21, which extends through an opening 19 in the lower cutter plate 6 of the trimmer. During oscillation of the lever, the lower cutter 5 for the razor part thus likewise performs an oscillating motion. By means of the driving connection 16, 17 between the two lower cutters 5, 6, this motion of the lower cutter 5 is also identically transmitted to the lower cutter 6 of the trimmer. The two lower cutters are thus displaced to and fro parallel to one another, while each individually engages fully with the upper cutter associated with it.

During the working movement of the lower cutters, only the springs 11 undergo a tipping motion on their abutments on the cutter head frame 1. That is to say the springs 12 reciprocate parallel to themselves by reason of the identically moved lower cutters, so that they remain always perpendicular to the lower cutter of the razor part, which ensures that the lower cutter which co-operates with the perforated cutter foil is pressed perpendicularly to the perforated cutter foil at all stages of operation (see FIG. 1). This is however, as already mentioned, especially important for a good shaving performance, because then the lower cutter always fully engages the perforated cutter foil. The pressing of the lower cutter 5 against the perforated cutter foil by tipping springs in fact produces, by reason of the pressure varying in amount and direction, a vibration of the lower cutter, so that during the working movement of the lower cutter a localised movement away from the perforated cutter foil takes place, so that the cutting action at these places on the perforated cutter foil is reduced or removed. In a trimmer such an effect is noticeable to a much less disturbing extent, because long hairs can be more easily cut, and it is thus not important to cut them off as close as possible to the skin.

By the measures described, with retention of the advantage of separated lower cutters for the razor part and the trimmer, an unobjectionable operation of the apparatus is thus achieved with a simple construction.

In the example according to FIGS. 3 and 4, an intermediate member 22 is provided as the driving connection between the lower cutters 5 and 6. This is formed as a frame, and extends between the cutter head frame 1 and the lower cutter 5 for the razor part, while at the same time the two springs 11 and 12 of a spring arrangement, which lie mechanically in series, engage on a small side 23 of the frame. The longitudinal sides 24 of the frame cooperate with sliding surfaces 25 provided on the cutter head frame 1, so that the intermediate member is guided in its longitudinal direction and thus performs an exact reciprocating motion.

The cutter head has two trimmers, and in fact an upper cutter 4 for a trimmer is formed on each longitudinal frame side 3. The lower cutter 6 for these trimmers is likewise formed as a frame, while a row of cutter teeth 9 is provided on each longitudinal side of the frame. This lower cutter is mounted by means of its central opening 26 on the intermediate member 22, while it is secured to it with a snap device, which is formed by noses 27 provided on the intermediate member. Moreover, on each of the longitudinal sides 24 of the intermediate member a lug 28 is arranged, in which a longitudinal slit 28a, contracting towards its mouth, is provided. By pushing these two slits over the driving pin 18 of the lower cutter for the razor part (for which purpose the ends of the slits are pressed somewhat apart at their mouth), the intermediate member 22 is pivotally connected with the driving pin 18, which also serves for connection with the driving portion of the apparatus, not shown here. By reason of the longitudinal extent of the slits 28a, the intermediate member 22 is however not only pivotally arranged, but also movable perpendicularly to the reciprocating direction of the lower cutter 5, on the driving pin 18. The contraction of the slits at their mouths serves to ensure that during assembly of the cutter head, the intermediate member cannot drop unintentional from the driv- .ing pin. In this way the driving connection of the two lower cutters 5 and 6 is formed, so that the lower cutter 6 of the trimmers follows identically the working movement of the lower cutter for the razor part.

The operation is similar to that of the constructional example already described. The intermediate member here operates as a guiding and driving part for the lower cutter of the trimmers and also as a guiding part for the spring arrangements. On driving of the lower cutter for the razor part, the intermediate member is identically driven, so that the springs 12 again are moved parallel to them selves, and always perpendicular to the lower cutter of the razor part, and only the springs 11 are tilted to some extent. Thus both lower cutters engage, each in themselves, with the associated upper cutter.

The intermediate member 22 furthermore has abutment surfaces 29 on the small sides 23 of the frame, which lie beneath the lower cutter 5 for the razor part, and against which the lower cutter can engage. If, during use of the razor part, a larger force is exerted on the latter, then the friction between upper and lower cutter increases, so that the driving part must supply more power, so that the same amplitude of oscillation remains.

A reserve of power can however only be provided, if the friction between the upper and lower cutters of the trimmers is reduced during larger shaving pressure, so that this energy can then be also available for the drive of the razor part. In these circumstances this is achieved, because whenever the shaving pressure exceeds the strength of the springs 12, the lower cutter 5 of the razor part, as a consequence of its displacement under the shaving pressure, comes to engage the abutment surfaces 29 of the intermediate member, and takes this with it. In this way, during the displacement of the intermedi ate member, the lower cutter 6 of the trimmers is disengaged from the upper cutters associated with it, so that the friction between the cutters of the trimmers is removed, or at least reduced.

In FIG. 5 a construction is shown, similar to the constructional example according to FIGS. 1 and 2, in which the spring arrangements are made of different kinds of springs. The springs 11 with an end engaging against the cutter head frame 1 are again coil springs. But as springs 12, which engage against the lower cutter 5 of the razor part, there are provided two blade springs extending in the longitudinal direction of the lower cutter 5, and lying on each side of the oscillating lever 20. These blade springs lie with their ends against the lower cutter 6 of the trimmer, while their central portion abuts against pins 30 provided on the lower cutter 5 for the razor part.

In the constructional example according to FIGS. 6

and 7, onlyga single spring arrangement 10 is provided. The intermediate member 22, forming the driving connection between the lower cutters 5, 6 here consists of a double spring plate, with a central opening 31 through which extends the oscillating lever 20, which operates the driving pin 18 of the lower cutter 5 of the razor part. The intermediate member is arranged on the driving pin 18 by means of two lateral lugs 28 having longitudinal slits 28a, so that it again follows identically the movement of the lower cutter 5 for the razor part. The lower cutter 6 of the trimmer is fixedly connected to the intermediate member 22, so that it is likewise driven via the latter. The power transmission from the spring 12 to the lower cutter 5 occurs through a fork 32 inserted between the driving pin 18 and the spring. By the identical movement of the lower cutter and the intermediate member, the spring 12 is again moved parallel to itself while remaining perpendicular to the lower cutter of the razor part, and only the spring 11 is tipped with certain limits.

Advantageously the strength of the spring 11 is exactly chosen only so much greater than the strength of the spring 12, so that only during use of the razor part, by the additional shaving pressure which occurs, the force of the spring 12 somewhat exceeds that of the spring 11, so that the lower cutter 6 of the trimmer is displaced somewhat from the associated upper cutter. In this way, again, on use of the razor part, the friction in the trimmer is sharply reduced, so that more power is available for the drive of the razor part. During use of the trimmer however, the cutting surfaces of the upper and lower cutter lie completely against one another, and thus ensure a good cutting action.

Naturally a series of variations from the described constructional examples are also possible, without going outside the scope of the invention; for example, intermediate members constructed otherwise can be used, and the number and kind of the spring devices can be varied.

I claim:

1. A cutter head for a dry shaver, comprising a cutter head frame, a perforated cutter foil arranged on the frame and acting as upper cutter for a razor part, a further cutter on at least one longitudinal side of the frame acting as upper cutter for at least one trimmer, lower cutters for the razor part and the trimmer, made as parts separate from one another, at least one spring arrangement, formed by two springs lying mechanically in series, of which one abuts :with one end on the cutter head frame, and the other abuts with one end on the lower cutter for the razor part, while the other ends of the two springs are in operating connection with the lower cutter for the trimmer, the strength of the springs which abut the frame, and press the lower cutter for the trimmer against the associated upper cutter being greater than the strength of the springs abutting against the lower cutter for the razor part, a driving connection between the two lower cutters, and means on only one of the lower cutters for direct engagement with a driving part of the shaver.

2. A cutter head according to claim 1, wherein the driving connection is an intermediate member, which on the one hand is connected to one of the two lower cutters pivotally, while being movable perpendicular to its reciprocating direction of motion, and on the other hand is connected fixedly to the other lower cutter.

3. A cutter head according to claim 2, in which the lower cutter for the razor part has a driving bar, for engagement by a fork-shaped driving member of the dry shaver, and the intermediate member is arranged on the driving bar of the lower cutter of the razor part 'by means of two lugs having longitudinal slits, and the lower cutter for the trimmer is fixedly connected to the intermediate member.

4..A cutter head according to claim 3, including two spring arrangements, wherein the intermediate member is formed as a second frame extending between the cutter head frame and the lower cutter for the razor part, while each of the two springs of each spring arrangement engages on a short side of the second frame.

5. A cutter head according to claim 4, wherein the intermediate member is guided in its longitudinal direction by its longitudinal frame sides on sliding surfaces of the cutter head frame.

6. A cutter head according to claim 3, wherein the intermediate member has abutment surfaces, with which the lower cutter for the razor part comes into engagement during use of the razor part, by reason of the additional razor pressure which arises, as soon as this exceeds the strength of the springs which abut the lower cutter of the razor part.

8 force of each spring supported by the cutter head frame is only so much greater than the strength of the spring which abuts against the lower cutter for the razor part, that during use of the razor part, by the additional shaving pressure, the lower cutter of the trimmer is disengaged from its upper cutter.

References Cited UNITED STATES PATENTS ANDREW R. JUI-IASZ, Primary Examiner 7. A cutter head according to claim 1, wherein the 15 G- GRAFEL, Assistant Examiner 

